Another option is use a push-pull (or push-push) pot on either the volume or tone and use it to add the middle pickup to any of the other positions. I've seen it done with 3-pickup teles. Obviously teles have a lever switch, but it's still just a 3-way regardless of toggle or lever mechanism. A little research may be in order, but it's doable.

I'll have a look and see what I can find!